Admins...if this doesn't belong here please feel free to move it.

New member but often lurking. I really need some help here.

2005 G35 Sedan. Was working fine and now no start condition exists. I've been searching for days and days and was going down the key losing connection road. But really, i am not sure.

When cranking the security light (i reckon the security light is the flashing red light we see all the time right?) is on solid.

Battery is good and have even tried multiple minutes of jumping in case it wasnt getting enough juice.

Checked all fuses. Checked fuel pump relay and tried a different one in it.

Dealer spoke of a comm box in top of trunk that could have become dislodged or something. No issues there either.

Car just cranks and cranks.

The key fob will unlock doors, trunk etc..

I understand some might say keep searching but i though maybe with having a new thread about this we might get some new ideas.

Thanks
B

 

Does your car still have the factory head unit? If so, disconnect your radio and cig lighter. See if that works.

 

can you expand on this idea? whats the thinking?

 

A little over two years ago, my '05 sedan had trouble starting. It would just crank as though the battery was weak except I had a brand new battery. It would take a few attempts each time to finally get it to start.

I did a google search and found stories of other G35 owners (and I think they were all sedan owners, strangely) who had the same problem. They all traced it back to their stock head units. The head units were drawing a lot of power even when the car was turned off.

Upon learning this, I went outside and disconnected all of the electronics from the center console. The car started right up! I then reconnected the cigarette lighter. The a/c controls were left disabled, but it was still blowing cold, I just couldn't adjust the temperature, no biggie. Shortly after that I had trouble starting again. Through deductive reasoning I figured that it must have been the cigarette lighter that I reconnected. I disconnected the lighter again and the car started just fine. So it must have been the combo of the head unit and lighter. It doesn't make sense to me either, but I drove without a radio and cig lighter for 3 months and the car started fine everyday.

I eventually got a full color, dvd, touchscreen pioneer head unit. I connected everything including the cig lighter. It's been two years (almost exactly) and the car has started reliably everyday.

 

Thanks for the note and explanation.

This car doesn't have any lack of cranking power...rather it just isn't firing up.

 

As though the battery is weak, right? That's how it was with me.

 

no sir...cranks really fast as normal.

 

My guess it has something to do with the immobilizer feature since your security light is on. Since I've got nothing I'll say check the FSM for possible solutions, if you don't have one look up psedog here, he's a former member that has listed links for all G model's FSM's in a post somewhere.

 

Thanks all, i really appreciate the input. I will make sure to post the fix (if we ever get one) on here also.

I was going the immobilizer way but i swear i read if that was the case they FOB wouldnt work for trunk and doors.

 

Gents. Seems it was the battery. I cant believe all the paths i went down in error. So, although I read and seen tons of threads mentioning the battery there was always a following post speaking to how that couldnt be it. So, for future folks looking lets answer some specific questions.

1. Didn't think it was the battery because:
all lights (dash, head etc) worked fine.
battery was fully charged
starting was tried with a jump from another vehicle
starting was tried with another vehicles battery (dont understand why this didnt work)
security light was solid when key in ON position
car cranked fast and seemingly solid
cooling fans came on right away and stayed on

...if we can address each of those points i think we will help future 35 drivers.

And, thanks for all the help guys.

 

Did you happen to take a Voltage reading on the battery? I'm interested to know what the voltage was. There may be a system (ie, fuel injuection maybe) which has a high nominal voltage, which would create an issue with a dying battery. Something for owners to know about...

 

yup. Battery tested good through entire process.